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キーワード:
Cram rule; Felkin-Anh model; diastereoselectivity; ab initio calculations; transition states
要旨:
The reaction mechanism of the LiH addition to alpha-chiral ketones and acylsilanes was calculated at the ab initio MP2/6- 311+G (circlecircle)//RHF/6-31G(circle) level. The selectivities predicted on the basis of the computed transition states and reaction barriers compare well with the experimental data, For compounds possessing very large groups, anti-Cram selectivity was found; silicon-containing compounds should show the same types of selectivity as their carbon analogs. The calculations suggest that a revision of the Felkin-Anh model is necessary and a proposal for such a revision is given, (C) Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002.
